1. Field of the Invention
The present invention relates to a self-diagnostic circuit and to a self-diagnostic method which detect an error in an integrated circuit.
2. Description of Related Art
Regardless of the device in which it is installed, an integrated circuit is required to have high reliability. In order to improve reliability, an integrated circuit may include a self-diagnostic circuit. The self-diagnostic circuit monitors operation in the integrated circuit, and detects failure and performance deterioration of the integrated circuit.
JP-A-HEI4-245309 discloses a semiconductor device which has such a self-diagnostic circuit.
JP-A-HEI4-245309 discloses a digital controller that has counters to count a number of retries for each diagnostic item in the integrated circuit, and indicates that an error is a serious error when the number of retries is large (i.e., over a predetermined threshold).
However, the present inventor recognized that in the technology of JP-A4-245309, since a counter was provided for every diagnostic item, and the number of diagnostic items also increased with increased scale of the integrated circuit and more advanced features, there was a problem in that the circuit scale of the self-diagnostic part also increased.